1. Field of the Invention
The present invention relates to a recording apparatus provided with a recording head for expelling ink droplets and particularly to a cleaning device for recording head.
2. Related Art
The main body of an ink jet recording head has an extremely small size and is capable of color printing if inks having different colors are used. Accordingly, an ink jet color printer has been put into practical use which includes a carriage provided with a black recording head for expelling a black ink and a color recording head for expelling yellow, cyan and magenta inks to enable text printing with a black ink as well as full-color printing.
Such an ink jet recording head is disadvantageous in that since an ink pressed in a pressure-producing chamber is jetted onto a recording paper in the form of ink droplet from a nozzle opening, the ink exhibits a raised viscosity or solidifies due to the evaporation of ink solvent or attracts dust or paper dust to cause malprinting.
In order to overcome these disadvantages, an ink jet recording apparatus normally includes a capping means for sealing the nozzle opening in the recording head while printing is not effected to prevent ink drying as well as a cleaning means which comes in sliding contact with the nozzle plate to give physical resolution to clogging in the nozzle opening.
Such a cleaning means is in the form of a blade formed by a plate made of an elastic material such as rubber. The cleaning mechanism is arranged such that when the carriage moves the recording head back and forth with the cleaning means protruding to a position at which it can come in elastic contact with the nozzle plate of the recording head, the tip of the blade can scratch dust and ink dregs off the nozzle plate with the ink.
Since the cleaning blade is brought into contact with the side of the recording head shortly before it comes in elastic contact with the nozzle plate of the recording head so that the ink containing paper dust or solid content is wiped off the cleaning blade, it can stay clean itself when applied to a cleaning operation for the nozzle plate of the recording head. However, this cleaning mechanism is disadvantageous in that when the cleaning blade leaves the recording head shortly after the termination of the cleaning operation to release the elastic force, it springs back to cause the ink wiped to fly in the form of droplets that stain the adjacent recording head and the interior of the housing.
Another disadvantage is that the prolonged use of the recording head causes the ink to solidify and accumulate on the side thereof. The ink thus accumulated moves to the cleaning blade from which it then stains the recording head, impairing the effect of the cleaning blade of cleaning the nozzle plate. In order to overcome this difficulty, a cleaning mechanism is proposed comprising another cleaning member provided in a non-printing zone for scratching ink, dust and ink dregs off the cleaning blade whereby the carriage is allowed to move to the cleaning member prior to the beginning of cleaning operation where the ink is scratched off the cleaning blade, and then allowed to move back to the original position where cleaning operation then begins. However, this cleaning mechanism is disadvantageous in that since the carriage needs to perform an extra movement to remove the ink from the cleaning blade, it adds to the entire cleaning time.